Magnetoresistive sensors based in thin film multilayer stacks, which exploit the giant magnetoresistive effect or tunnel magnetoresistive effect, have an electrical resistance that depends on the relative orientation between the magnetic moment of a reference ferromagnetic layer (RL) and a sensing ferromagnetic layer (SL). The magnetic moment of the reference ferromagnetic layer is usually fixed by interfacial exchange coupling with an anti-ferromagnetic material such as iridium manganese (IrMn) or platinum manganese (PtMn). This coupling defines a preferred reference direction along which the reference layer is strongly pinned. The resistance of the sensor changes linearly with respect to a magnetic field applied along the reference magnetic layer if in the absence of an external field, the sensing layer magnetic moment lies at 90 degrees with respect to the reference direction, i.e., along the orthogonal direction.